Process for the production of formaldehyde from methane

Abstract

Formaldehyde is made from methane and a molecular oxygen containing gas by using a silica supported catalyst having less than 350 parts per million by weight of sodium and having a catalytically effective amount of V2O5. The low sodium form of the silica support can be made by washing silica gel or precipitated silica or by using a fumed silica. In general, the lower the sodium level, the better is the catalyst.

What is claimed is: 
     
       1. A process to make formaldehyde from methane comprising partially oxidizing methane with a molecular oxygen containing gas over a catalyst comprising V 2  O 5  on a silica support having a low sodium content of less than 350 ppm, said amount of V 2  O 5  being at least a catalytically effective amount and up to an amount where the V content is about 50% by weight of the catalyst. 
     
     
       2. A process according to claim 1, wherein the support is a silica selected from the group consisting of silica obtained from the hydrolysis of silicon tetraalkoxides, fumed silica, acid washed silica gel, acid washed precipitated silica and mixtures thereof. 
     
     
       3. A process according to claim 1, wherein the silica support has a BET nitrogen surface area of at least 1 m 2  /g. 
     
     
       4. A process according to claim 1, wherein the silica support has a sodium content of less than 100 ppm. 
     
     
       5. A process according to claim 4, wherein the silica support has a sodium content of less than 20 ppm. 
     
     
       6. A process according to claim 5, wherein the silica support has a sodium content of about 1 ppm or less. 
     
     
       7. A process according to claim 1, wherein the amount of V 2  O 5  expressed as wt % V, is an amount up to 15 wt % V. 
     
     
       8. A process according to claim 7, wherein the amount of V 2  O 5  is from about 0.5-15 wt % V. 
     
     
       9. A process according to claim 2, wherein the silica is a silica obtained from the hydrolysis of silicon tetraalkoxides and the sodium content is less than 4 ppm. 
     
     
       10. A process according to claim 9, wherein the sodium content is less than 2 ppm. 
     
     
       11. A process according to claim 1, wherein the silica support is an acid washed silica gel. 
     
     
       12. A process according to claim 1, wherein the silica support is an acid washed precipitated silica. 
     
     
       13. A process according to claim 1, wherein the temperature is up to 700° C. 
     
     
       14. A process according to claim 13, wherein the temperature is between 400° and 700° C. 
     
     
       15. A process according to claim 1, wherein the space velocity is 500 to 100,000 hr -1  at normal temperature and pressure.